Antibiotics and opioids are the top therapeutic categories prescribed by Dentists. Interestingly, factors associ- ated with prescribing behaviors of these medication classes are similar. Our preliminary data on dental pre- scribing demonstrates that high prescribers of opioids are also high prescribers of antibiotics. However, there is a current knowledge gap in our understanding of medication prescribing and overprescribing (for inappro- priate indications and/or excessive quantity/potency/duration) by Dentists. This gap is significant because Dentists prescribe 1 out of every 10 prescriptions (Rx) for both antibiotics and opioids in the US. Inappro- priate and appropriate use of antibiotic and opioids are a risk to patient safety, including: bacterial resistance, Clostridium difficile infection, opioid overdose, drug dependence and diversion. Opioid overprescribing is con- cerning because substance users commonly seek opioids from dentists, dentists infrequently use prescription drug monitoring programs (PDMP) and fatalities secondary to opioid use have been linked to dental prescrib- ing. Use of antibiotics for infection prophylaxis prior to dental procedures has been associated with C. difficile. Guidelines for infective endocarditis and prosthetic joint infection prophylaxis during dental procedures were recently updated, significantly reducing the number of patients requiring antibiotic prophylaxis. However, de- spite infection prophylaxis being the primary indication for antibiotics prescribed by dentists, our preliminary data shows only a small (0.7%) decrease in overall dental antibiotic prescribing. Although efforts are increas- ing to curtail inappropriate use of these medication classes, most interventions are focused on physicians and midlevel providers (nurse practitioners, physician assistants). Guided by preliminary data, we will be pursuing [2] specific aims: 1) [Assess] dental prescribing of antibiotics and opioid medications and identify patient and prescriber characteristics associated with high rates of overprescribing and 2) [Compare attitudes to- wards prescribing antibiotics and opioids for dentist with practices located in high and low prescribing com- munities across the United States.] The proposed study is aligned with the research priority areas of AHRQ (safer health care; improvements in health care practice, especially in ambulatory care) and 2 White House National Action Plans focused on antibiotic resistance and adverse drug events associated with opioid use. We propose to conduct a mixed-methods study to assess antibiotic and opioid dental prescribing based on American Dental Association treatment recommendations and identify factors related to prescribing. The ex- pected outcomes of this study include providing baseline data on the extent of antibiotic and opioid overpre- scribing by dentists, identification of barriers and facilitators to improving prescribing of antibiotics and opioids and selection of a pilot implementation project to improve the quality of dental care. Our long-term goal is to improve patient dental care by implementing interventions that will increase prudent antimicrobial use, de- crease opioid overprescribing and decrease serious adverse events.